Focus on APS Topical Groups

Quantum Information

By Nadia Ramlagan 

In just a few short years, the APS Topical Group on Quantum Information (GQI) has burgeoned into an important focal point for researchers across a wide range of fields, while maintaining its dedication to continued discussion and vitality of research on the foundations of quantum theory.

The field has diversified itself so much that across the wide table of what the GQI represents is a variety of contributions from applied math, engineering, and computer science–fields which traditionally do not see APS as their primary home.

“What is clear is that the field is still booming and growing; I think one interesting aspect is that we are seeing more and more cross-collaboration with different disciplines; areas that used to be disjoined like quantum gravity or condensed matter or statistical physics aspects like quantum chaos and randomness are now sharing interesting ideas. It speaks to the cross-disciplinary nature of our field, “said Past Chair Lorenza Viola.

Yet the umbrella of the GQI will always provide a welcoming home for those pursuing speculations in the foundations of quantum theory, Chair-elect David DiVincenzo believes. “From the philosophical implications of quantum mechanics to what do we mean by wave function collapse? And, is there an alternative to the conventional theory and interpretation of quantum mechanics?” he said.

A major trend in current research is superconducting qubits; a whole symposium will be dedicated to the topic at the 2009 March Meeting. Superconducting qubits provide a new means of manipulating light one photon at a time by superconducting devices. “It is a very robust corner of the group right now, it probably constitutes a third of all research activity, as measured by contributed papers at the March Meeting,” said DiVincenzo.

Superconducting devices are one of a number of possible technologies for storing and processing data in the physical realization of quantum computers. “This a big long-term goal that people would like to get to, and that is being attacked at all levels except the commercial, as no one has a large, working quantum computer yet”, adds DiVincenzo. In addition, there is a bulk of research exploring the many different approaches to the sub-systems involved in the physical realization of quantum computers, areas that are well represented in the GQI.

Several smaller (in terms of number of researchers working within them) areas represent equally important future directions in fundamental research for the GQI community, including Quantum Shannon Theory. Denoting the application of the mathematical techniques of communication theory to problems in quantum mechanics, Quantum Shannon Theory has overlapped with areas that are more recognizable to theoretical physics, resulting in new perspectives and approaches to the theory of many-body quantum systems.

“For example, it’s recognized that mathematical characterizations of quantum entanglement are very effective in building new theories for quantum many-body systems and also new approaches to the simulation of quantum many-body systems,” said DiVincenzo. A symposium at the 2009 March Meeting will highlight recent Quantum Shannon Theory developments. 

“GQI is a very young group, but nevertheless I’m very pleased with our presence at the March Meeting and the breadth of activities that we’ve been able to ensure,” said Viola. At the 2007 March Meeting in Denver, GQI held a total of 13 sessions that the group has either sponsored or co-sponsored, while last year in New Orleans the number of sessions increased to 20, on top of several heavily attended tutorials. While the program for the upcoming 2009 meeting in Pittsburgh is still in the works, the group will continue to have a significant number of invited sessions. Thus far, at least 4 sessions have been confirmed, 2 are pure GQI sessions and 2 are co-sponsored with Division of Condensed Matter Physics. 

“I think these things should be taken as a strong indication of the scientific solidity and visibility of the group within the broad physics community. We are also putting a lot of emphasis on educating young students and researchers to attract them to the area,” said Viola.

The group awards “Best Student Paper” $500 prizes at the March Meeting, open to both undergraduate and graduate students. In the future, the GQI has ambitious plans to create more major prizes for recognizing outstanding achievements in theory and experiments in quantum information processing among both young and established researchers.

GQI emerged out of a petition by Anton Zeilinger of the University of Vienna and Daniel Greenberger of the City College of New York (CUNY). The letter, presented to APS in 2002, expressed concern over a lack of unified dissemination of new knowledge in the wake of ballooning interest in the field from physicists of all sub-disciplines. However, the first bylaws weren’t established until three years later, in 2005.

“We started off having roughly 600 members and now we are at almost 900. And of course now the growth is continuing at a slower pace as eventually things will have to stabilize a bit; but I think these numbers are very impressive because we are talking about just a few years of existence,” said Viola.